The use of alternate fuels in diesel engines has become very significant due to the fast depletion of conventional fossil fuels. Solid wastes like plastics cause several environmental problems and hindrances to existence of plant and animal life. This paper focuses on use of waste plastic oil as fuel. The combustion characteristics of a diesel engine fueled with plastic oil as fuel derived from the pyrolysis process. The blends of 15% waste plastic oil and 25% waste plastic oil with diesel are prepared on volume basis and tested on a single cylinder CI engine. The properties of WPO blends are found to be similar to that of diesel and within the ASTM standards. The combustion characteristics like In-cylinder pressure, Rate of pressure rise and Net heat release rate of the WPO blends exhibited characteristics competent with that of straight diesel. The curves indicating the ignition delay and maximum cylinder pressure are also presented for the blends. The ignition delay increased with increase in blend percentage and the peak pressure reduced with higher blends. The heat release rate of the WPO blends is slightly lower compared to diesel.